This research is part of a general program, the goal of which is to discover the relation of general intelligence, within the retardate range, and parameters of underlying psychological processes. Previous research has related intelligence to parameters of processes of the intermediate level such as learning, attention and memory. The present research addresses the problem of processes of greater complexity, those basic to simple language learning. The experimental methodology to be used is that of Miniature Language Systems (MLSs) which tap two fundamental aspects of language acquisition: semantic and syntactic. Systematic variations of MLSs will provide tests of the following major hypotheses: (1) the syntax of semantically empty signs is relatively difficult to learn; (2) in general, semantic structures are easier to acquire than syntactic; (3) this is especially true for retardates; (4) syntactic rules are easier learned if these are consonant with existing conceptual knowledge; (5) it is relatively easy to learn syntactic rules using signs with rich and salient referents; (6) learning the syntactic ordering of signs referring to action is easier if the action sign (verb?) follows in sequence a nonaction sign (noun?); and (7) the generalization of syntactic rules to semantic classes is more difficult for retardates than is the ordering of specific signs. Experiments are proposed with institutionalized retarded subjects that will provide tests of these hypotheses.